What s the difference between compiled and interpreted language

Question

After reading some material on this subject I m still not sure what the difference between a compiled language and an interpreted language is  I was told this is one of the differences between Java and JavaScript  Would someone please help me in understanding it

User · Answer

Here is the Basic Difference between Compiler vs Interpreter Language.

Compiler Language

Takes entire program as single input and converts it into object code which is stored in the file.
Intermediate Object code is generated
e.g: C,C++
Compiled programs run faster because compilation is done before execution.
Memory requirement is more due to the creation of object code.
Error are displayed after the entire program is compiled
Source code ---Compiler ---Machine Code ---Output

Interpreter Language:

Takes single instruction as single input and executes instructions.
Intermediate Object code is NOT generated
e.g: Perl, Python, Matlab
Interpreted programs run slower because compilation and execution take place simultaneously.
Memory requirement is less.
Error are displayed for every single instruction.
Source Code ---Interpreter ---Output

User · Answer

Interpreted language is executed at the run time according to the instructions like in shell scripting and compiled language is one which is compiled  changed into Assembly language  which CPU can understand   and then executed like in c

User · Answer

It is a very murky distinction  and in fact generally not a property of a language itself  but rather of the program you are using to execute code in that language   However  most languages are used primarily in one form or the other  and yes  Java is essentially always compiled  while javascript is essentially always interpreted   To compile source code is to run a program on it that generates a binary  executable file that  when run  has the behavior defined by the source  For instance  javac compiles human-readbale  java files into machine-readable  class files   To interpret source code is run a program on it that produces the defined behavior right away  without generating an intermediary file  For instance  when your web browser loads stackoverflow com  it interprets a bunch of javascript  which you can look at by viewing the page source  and produces lots of the nice effects these pages have - for instance  upvoting  or the little notifier bars across the top

User · Answer

What   s the difference between compiled and interpreted language    The difference is not in the language  it is in the implementation   Having got that out of my system  here s an answer    In a compiled implementation  the original program is translated into native machine instructions  which are executed directly by the hardware  In an interpreted implementation  the original program is translated into something else   Another program  called  the interpreter   then examines  something else  and performs whatever actions are called for    Depending on the language and its implementation  there are a variety of forms of  something else    From more popular to less popular   something else  might be   Binary instructions for a virtual machine  often called bytecode  as is done in Lua  Python  Ruby  Smalltalk  and many other systems  the approach was popularized in the 1970s by the UCSD P-system and UCSD Pascal  A tree-like representation of the original program  such as an abstract-syntax tree  as is done for many prototype or educational interpreters A tokenized representation of the source program  similar to Tcl The characters of the source program  as was done in MINT and TRAC    One thing that complicates the issue is that it is possible to translate  compile  bytecode into native machine instructions   Thus  a successful intepreted implementation might eventually acquire a compiler   If the compiler runs dynamically  behind the scenes  it is often called a just-in-time compiler or JIT compiler   JITs have been developed for Java  JavaScript  Lua  and I daresay  many other languages   At that point you can have a hybrid implementation in which some code is interpreted and some code is compiled

User · Answer

A compiler  in general  reads higher level language computer code and converts it to either p-code or native machine code  An interpreter runs directly from p-code or an interpreted code such as Basic or Lisp  Typically  compiled code runs much faster  is more compact  and has already found all of the syntax errors and many of the illegal reference errors  Interpreted code only finds such errors after the application attempts to interpret the affected code  Interpreted code is often good for simple applications that will only be used once or at most a couple times  or maybe even for prototyping  Compiled code is better for serious applications  A compiler first takes in the entire program  checks for errors  compiles it and then executes it  Whereas  an interpreter does this line by line  so it takes one line  checks it for errors  and then executes it    If you need more information  just Google for  difference between compiler and interpreter

User · Answer

As other have said  compiled and interpreted are specific to an implementation of a programming language  they are not inherent in the language  For example  there are C interpreters  However  we can  and in practice we do  classify programming languages based on its most common  sometimes canonical  implementation  For example  we say C is compiled  First  we must define without ambiguity interpreters and compilers  An interpreter for language X is a program  or a machine  or just some kind of mechanism in general  that executes any program p written in language X such that it performs the effects and evaluates the results as prescribed by the specification of X  A compiler from X to Y is a program  or a machine  or just some kind of mechanism in general  that translates any program p from some language X into a semantically equivalent program p  in some language Y in such a way that interpreting p  with an interpreter for Y will yield the same results and have the same effects as interpreting p with an interpreter for X  Notice that from a programmer point of view  CPUs are machine interpreters for their respective native machine language  Now  we can do a tentative classification of programming languages into 3 categories depending on its most common implementation   Hard Compiled languages  When the programs are compiled entirely to machine language  The only interpreter used is a CPU  Example  Usually  to run a program in C  the source code is compiled to machine language  which is then executed by a CPU  Interpreted languages  When there is no compilation of any part of the original program to machine language  In other words  no new machine code is generated  only existing machine code is executed  An interpreter other than the CPU must also be used  usually a program  Example  In the canonical implementation of Python  the source code is compiled first to Python bytecode and then that bytecode is executed by CPython  an interpreter program for Python bytecode  Soft Compiled languages  When an interpreter other than the CPU is used but also parts of the original program may be compiled to machine language  This is the case of Java  where the source code is compiled to bytecode first and then  the bytecode may be interpreted by the Java Interpreter and or further compiled by the JIT compiler   Sometimes  soft and hard compiled languages are refered to simply compiled  thus C   Java  C  C   are said to be compiled  Within this categorization  JavaScript used to be an interpreted language  but that was many years ago  Nowadays  it is JIT-compiled to native machine language in most major JavaScript implementations so I would say that it falls into soft compiled languages

User · Answer

Java and JavaScript are a fairly bad example to demonstrate this difference  because both are interpreted languages  Java  interpreted  and C  or C     compiled  might have been a better example      Why the striked-through text  As this answer correctly points out  interpreted compiled is about a concrete implementation of a language  not about the language per se  While statements like  C is a compiled language  are generally true  there s nothing to stop someone from writing a C language interpreter  In fact  interpreters for C do exist    Basically  compiled code can be executed directly by the computer s CPU  That is  the executable code is specified in the CPU s  native  language  assembly language    The code of interpreted languages however must be translated at run-time from any format to CPU machine instructions  This translation is done by an interpreter   Another way of putting it is that interpreted languages are code is translated to machine instructions step-by-step while the program is being executed  while compiled languages have code has been translated before program execution

[java] What's the difference between compiled and interpreted language?

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